With conventional agricultural tractors etc., the housings of the drive train serve simultaneously as the load-bearing structure of the vehicle. These housings include, for example, a rear axle housing, a transmission housing, a clutch housing, an oil sump, and a front axle housing. All the housings are bolted to one another and therefore form a structural combination on which a cab, a radiator arrangement with heat exchanger, radiator fan and surrounding structures, an engine etc. are mounted. In addition, at both ends of the tractor hydraulic lifting devices are usually attached to the housings, which are generally designated as front and rear power lifting devices.
In specific travel situations in uneven terrain front and rear axles are restricted, with the result that high torsion forces are exerted on the load-bearing housing combination. If the vehicle is ballasted at the front and has a heavy attachment device secured to the rear, which is raised from the ground, there is an additional flexural stress imposed on the load-bearing transmission train combination in the direction of travel. The scale of these forces and torsions increases with the distance between the rear axle and the front axle. These forces can only be absorbed by the housings to a certain degree. Because the distance between the wheel axles is constantly increasing, in particular with vehicles with high engine capacity, and because with these vehicles the stress is also increasing as a result of equipment attachments becoming larger and larger, this type of design is encountering its structural limits.
From CZ 288 674, in addition to the housing combination, a carrier frame is provided, which is bolted to the housing combination over the length of the vehicle and therefore absorbs the stresses referred to above. This carrier frame is located above the transmission combination and results in an increase in the structural space required, since the radiator arrangement etc. is placed on this frame. Specifically in the area of the front of the vehicle, in the area of which the radiator arrangement and the engine are placed, the vehicle becomes perceptibly higher. Due to the high vehicle engine cover there is only a restricted free view to the front. This is of particular importance if equipment attachments are located in the front area of the vehicle which the driver must be able to observe in order, for example, to stay on track or be able to identify obstacles. In addition to this, there is the risk that, in part, the provisions of the law regarding a free view of the area in front of the vehicle engine cover can no longer be respected.
The design shown in CZ 288 674 of a carrier frame running continuously from front to rear accordingly requires a perceptible increase in the height of the vehicle, in particular in the area of the vehicle front, which results in an impairment of the driver's view to the front.